Effect of high temperature processing under different environments on physical and surface properties of rubberwood(Hevea brasiliensis)

摘要

Plantation grown Hevea brasiliensis (rubber-wood) was thermally processed in a vacuum-pressure oven in the temperature range of 150-240 °C under two inert environments (vacuum and nitrogen gas) and normal atmospheric pressure (air). Effect of heat treatments on various physical properties of rubberwood such as equilibrium moisture content (EMC), specific gravity, water uptake, shrinkage, colour and surface roughness profiles was evaluated and compared with untreated wood. The EMC of rubberwood wasfound to be reduced by almost half while specific gravity was reduced slightly after heat treatment. The intensity of darker brown colour was increased with increasing heat treatment temperatures and colour change was observed to be uniform throughout the wood blocks. Dimensional stability, water resistance, colour and surface quality were observed to be improved after thermal processing of rubberwood at moderately high temperatures under inert environments without affecting other properties deleteriously. Based on improved properties, heat treated rubberwood was found to be suitable for nonstructural applications such as flooring, siding, paneling etc.